Companies store and analyze massive data sets, such as search logs, web content collected by crawlers, and click streams collected from a variety of web services. Due to the size of these data sets, traditional parallel database solutions can be prohibitively expensive. Instead of a traditional database, the data may be stored in a stream. A stream is a file to which new data may be appended. For example, an application may create a stream consisting of click data and add each day's click data to the existing stream.